Recently, there has been a trend among hardware designers to implement serial interfaces between hardware components. Serial interfaces are high-speed point-to-point interfaces between box-to-box, board-to-board, or chip-to-chip interfaces. Serial interfaces reduce interconnect complexity, wires and space compared to parallel interfaces. Serial interfaces operate according to a differential mode wherein differential mode signals propagate through a pair of traces. One trace carries a conventional signal, while the other trace carries a signal that is exactly equal and opposite.
Often, the layout of the pin assignments of the interfaced components calls for the traces to be switched at the receiving component. Typically, the traces are crossed over on another layer of the printed circuit board (PCB) in order to maintain impedance matching between the traces. However, swapping the traces on different PCB layers increases the costs of manufacturing a PCB having integrated circuits and differential traces.